Zcash + Ethereum Why Two Blockchains Are Evolving Together

The blockchain world can feel unfriendly and uncollaborative at times, with supporters of competing technologies often criticizing each other professionally (and personally).

But, it isn't all competition. Progress on incorporating zcash's anonymity into ethereum serves as a reminder that there's more going on than just Twitter and Reddit in-fighting, and further, that there's an ongoing, fragmented effort to make major blockchain networks more compatible.

So far, the two blockchain networks have at least three publicly-known, semi-official projects. (Some smaller examples are that ethereum creator Vitalik Buterin is an advisor to zcash, and that zcash creator Zooko Wilcox went so far as to put a heart in the title of his

">Devcon presentation).

Zcash CTO Nathan Wilcox described the projects as the inevitable result of an organic interaction between developers in the cryptocurrency space.

He explained that, in his view, many cryptocurrencies offer unique value.

"These systems can adapt and adopt improvements from the others, but there are always going to be trade-offs that distinguish them," he said, using bitcoin, ethereum and zcash as examples.

On a sociological level, the sentiment bucks the trend toward blockchain "maximalism", or the idea that the technology is a winner-take-all competition.

Wilcox said he believes that it's better for everyone if it's easy to move between major chains.

He told CoinDesk:

"By enabling smooth interaction between them, we connect the whole network of users in a way that still allows individual users to use the trade-offs best for them."

'ZoE' grows up

One project is effectively trying to combine the technologies.

The idea behind zcash on ethereum (ZoE), an informal initiative, is what it sounds like: adding the technology behind zcash to ethereum. (It started as “baby ZoE,” grown from a Cornell bootcamp last summer).

As you’ve probably heard, ethereum's main advantage is a more flexible smart contract language, allowing developers to write nearly any self-executing program they want. Meanwhile, zcash is unique in that it uses zk-SNARKS, cryptography that hides senders, receivers and the balances of each address.

It's worth noting that Hawk is another initiative with the same goal of privatizing ethereum transactions, although it's a more formal research paper, and the technical implementation is different.

On one hand, although blockchains are generally launched to allow users to take advantage of new features, the goal here, interestingly, seems to be to make blockchains more like each other.

As Wilcox noted, the expectation is that the two projects will continue to have trade-offs.

Another quest

Ethereum's Christian Reitwiessner, who’s been leading development of the ethereum smart programming language, Solidity, was one developer to pick up the baton from there.

The ethereum project emphasized incorporating zk-SNARKS from the beginning, he said, and that was one of the "driving forces" for him getting involved in ethereum in the first place.

More recently, he had an opportunity to explore them in detail to see how they could use the tech for ethereum's smart contracts, publishing a long blog post on their mysterious inner-workings in December. Soon after, zcash engineer Ariel Gabizon suggested that they try to build something in Berlin.

Reitwiessner emphasized that there are actual use cases for the anonymity provided by zk-SNARKS. For example, voting is a much-tested blockchain use case, and an application stemming from ZoE could afford voters extra anonymity.

"That way you get an anonymous system where nobody sees who voted for who, but the counting is done in a decentralized way on a blockchain," he explained.

Further, it may be used to shield other non-financial information, where the applications might not be immediately obvious yet.

The idea relies on someone's encrypted GPS coordinates being posted to the blockchain once a day. The person could then pull it out as it comes in handy. Perhaps people could even cryptographically sign to further verify that the person was in a certain location on a certain day.

He added that the goal is to add the technology to ethereum, maybe as soon as Metropolis, one of the planned ethereum upgrades that will introduce a new blockchain that nodes and miners need to shift to.

In addition, he plans to work on “tooling” that will make it easier for developers to take advantage of zk-SNARKS for their own use cases.

Bridging blockchains

Then there’s another project, Project Alchemy. The plan is to construct a "bridge" between zcash and ethereum, as Reitwiessner put it.

Joining various blockchains isn’t exactly a new idea, of course. There are sidechains, and then experiments like Cosmos and Polkadot, sometimes called the "Internet of Blockchains," that want to build a bridge between the different networks.

"They're similar because the goal is to connect the whole 'meta-network' of different blockchains which have different feature trade-offs into one ecosystem with a reinforcing network effect," Wilcox said.

But, there's one difference.

"I see Alchemy as encompassing a broader set of mechanisms to streamline interaction and I value free floating exchange prices over automated price pegs because they seem to offer better individual choice," he said.

'Alchemy' is the process of transmuting substances into other forms, and as such, the goal of Project Alchemy in particular is to make it easier to swap zcash directly for ether without a centralized entity managing the trade.

The process starts with an ether seller opening up an "order" smart contract on ethereum, which sits there, and won’t execute until someone fulfills it until the seller receives the correct amount of zcash at a particular address.

Then, it automatically executes with no third-party involvement.

Of course, there need to be enough people conducting trades on the platform to make it quick to use.

There are plans to try to bridge other blockchains. Project Alchemy is a follow-up to BTC Relay, a similar project that allows users to pay for ethereum contracts with bitcoin. And, Wilcox noted that they plan to work on a similar project between zcash and bitcoin in the future.

Ongoing collaboration

And, collaboration is far from limited to ethereum and zcash.

Zooko Wilcox noted that Zcash Company recently submitted a version of Hashed Time-Lock Contracts, perhaps best-known for its role in the Lightning Network, for the Bitcoin Core wallet. The hope is that it might be used for cross-chain atomic transactions, potentially another way to bridge blockchains.

Nathan Wilcox summed up the overall benefits of such projects as the diversity and inclusion of ideas.

”I feel having different teams with different styles, philosophies and goals is better overall for the entire cryptocurrency space. That leads to more experimentation and exploration of the design space, and it reaches different target audiences," he said.

Overall, he expressed a hope that such projects would help the technology's disparate communities become more intertwined.

He concluded:

"Tribalism and reputation-grand-standing are a detracting force slowing down the evolution of the space, so we try to avoid them."